1. Field of the Invention
The present invention relates to computational circuits for calculating addition, multiplication, comparison, quantizing and exponentials of substantially analog values.
2. Description of the Related Art
In the conventional digital computers, computations are performed using many combinations of simple digital logic circuits. Digital computation is accurate and redundant. However, it is limited due to the large equipment costs required for high precision manufacturing of the digital logic circuits. Analog computation was frequently used mainly for solving differential equations, but because of the limitations of digital electronics noted above, analog computation is attracting attention again. Operational amplifiers are used in conventional analog computation. However, a lot of electric power is necessary for large scale analog computation because it is driven by current. As a result, it is difficult to provide a practical circuit for solving a large scale complicated calculation.